21187283 has 16 divisors (see below), whose sum is σ = 23632896. Its totient is φ = 18869760.

The previous prime is 21187279. The next prime is 21187303. The reversal of 21187283 is 38278112.

It is not a de Polignac number, because 21187283 - 2² = 21187279 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21187213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67535 + ... + 67847.

It is an arithmetic number, because the mean of its divisors is an integer number (1477056).

Almost surely, 2^21187283 is an apocalyptic number.

21187283 is a deficient number, since it is larger than the sum of its proper divisors (2445613).

21187283 is a wasteful number, since it uses less digits than its factorization.

21187283 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494.

The product of its digits is 5376, while the sum is 32.

The square root of 21187283 is about 4602.9645881758. The cubic root of 21187283 is about 276.7101496146.

The spelling of 21187283 in words is "twenty-one million, one hundred eighty-seven thousand, two hundred eighty-three".